#include <bits/stdc++.h>
using namespace std;
int n;

int t[10000];

int lowbit(int x) {
    return x & (-x);
}

//求前n项的和
int query(int n) {
    int sum = 0;
    while (n != 0) {
        sum += t[n];
        n -= lowbit(n);
    }
    return sum;
}

void add(int x, int v) {
    while (x <= n) {
        t[x] += v;
        x += lowbit(x);
    }
}

int a[1000];

int main() {
    for (int i = 1; i <= n; i++) {
        a[i] = true;
    }
    a[1] = false;
    for (int i = 2; i * i <= n; i++) {
        if (a[i]==false) cotinue;
        for (int b = i; i * b <= n; b++) {
            a[i * b] = false;
        }
    }

    return 0;
}
